Foo Fighters fought back against anti-gay protesters at a concert this weekend, singing in celebration of "man muffins". The rockers held a surprise gig outside their tour venue, mocking representatives from the extremist Westboro Baptist Church.

The stunt took place in Kansas City on Friday, where representatives from the notorious Westboro Baptist Church were picketing outside the Sprint Centre. As fans mingled in the street, out rolled a flat-bed lorry, bedecked with hay bales, American flags, and the Foos in fancy dress. "How we all doing?" asked frontman Dave Grohl, wearing a long wig and cowboy hat. "We got a song for ya!"

Together with his band, Grohl performed Keep it Clean (Hot Buns), a gay love song they debuted last month. "Driving all night, got a hankering for something," he sang, "Think I'm in the mood for some hot man muffins/ Mmmm, sounds so fine, yes indeed." Grohl told the crowd: "I don't care if you're black or white or purple or green, whether you're Pennsylvanian or Transylvanian, Lady Gaga or Lady Antebellum, it takes all kinds! Men loving women, and women loving men, and men loving men, and women loving women … God bless America!" They later repeated the performance inside, as part of their official gig.

Although Foo Fighters have not previously been vocal about gay rights, they became a target for the Westboro Baptist Church after posting their Hot Buns video in August. "The entertainment industry is a microcosm of the people in this doomed nation: hard-hearted, hell-bound, and hedonistic," Fred Phelps wrote on the church's website. "[The Foo Fighters] have a platform and should be using it to encourage obedience to God; instead they teach every person who will listen all things contrary to him: fornication, adultery, idolatry, fags." Founded in 1955, Phelps's organisation is infamous for its headline-grabbing protests, including pickets at the funerals for Michael Jackson and Ronnie James Dio.